Testing system for telephone cord circuits



J. F. TOOMEY TESTING SYSTEM FOR TELEPHONE CORD CIRCUITS Nov. 8; 1927. 1,648,079

I 2 INVENTOR j JE 1501746? I C BY ATTORNEY Patented Nov. 8, 1927.

UNITED STATES JOHN F. TOGMEY, on NEW Your, N. Y., AssreNoa ro' AMERICAN TELEPHONE AND re iance PATIENT OFFICE.

TELEGRAPH CGIVIPAINY, A COBFORATION OF NEW YORK.

TESTING SYSTEIII'FOR TELEPHONE CORD CIRCUITS.-

Application filed July 8,

This invention relates to testing systems more particularly adapted for testing the various apparatus associated with telephone cord circuits. 1

One of the objects of the invention con sists in providing testing equipment which, when connected to a cord circuit, affords means to determine Whether the supervisory relays and other apparatus associated with the cord circuit function properly under conditions which are either approximately the same or are more severe than those experienced in actual service.

Another object of the invention consists in providing a system of the above character which is simple and accurate in its operation.

Other and further objects of the invention will appear from the following description, when considered in connection with the accompanying drawing.

In the drawing, Figure 1 illustrates a diagram of an operators cord circuit, and Fig. 2 illustrates a testing system with which the cord circuit of Fig. 1 may be associated.

The cord circuit appearing in Fig. 1 terminates in the usual plugs 5 and 6 which are adapted to be inserted in the usual line jacks (not shown) that are installed in a switchboard. The usual supervisory relays 7 and 8 are associated with the cord circuit, and said cord circuit may be used to establish a connection between two telephone lines.

Associated with the said relays in the cord circuit are supervisory signals 9 and 10. W hen a telephone connection is desired, the plugs and 6 are inserted in line jacks (not shown) in which the said lines terminate at a switchboard.

In addition to the usual line jacks, special jacks 12 are provided at each switchboard section by means of which the cord circuits located in each switchboard section may be connected with testing apparatus. In" addition to the iacks 12, jacks 11 are also provided to make certain tests to determine the continuity of the conductors of the cord circuit.

The testing circuit B comprises a milliammeter 13 which has associated with it adjustable resistances 14c, 15 and 16 whereby conditions simulating those in actual prac-- tice are set up. The resistances 17 and relay 18 constitute a. dummy cord which simulates the characteristics of an operators ord circuit! 1925. Serial No. 42,265.

In the operation of the improved system, key 19 is actuated and connects the resistance l7 and relay 18 across the circuit; The resistances 14;, 15 and 16 are adjusted to give the proper saturate, operate and release values, respectively, to which the elements of the cord circuit should respond when subjected to these tests. The key 19 is re leased after these values are set up, and the circuit is ready for testing.

The first part of the test is made by in sorting one of the plugs of the particular cord circuit under test into jack 12. It will be assumed that plug 5 is the plug selected and inserted in jack 12 and a circuit is closed from battery, lamp 9, sleeve contacts of plug 5 and jack 12, left low resistance winding of relay 20 to ground. The closing of this circuit causes lamp 9 to'light and also operates relay 20 which connects ground from the normal contact 52 of key 21, conductor 44, right make contact of relay 20, inner back contact of relay 22, winding of relay 23, through slow speed interrupter 24 to battery. The closure of this circuit causes relay 23 to be intermittently operated by the interrupter 24 about sixty times a minute. The operation of relay 23 at this time, however, does not close the testing circuit which is open at the right contact of relay 25. When the plug of the cord circuit under test is inserted in jack 12, a second circuit is closed from bat tery over the ring side of the cord and ring side of the plug and jack, left-hand winding of relay 26, back contacts of relays 25 and 23 to ground. This latter circuit constitutes a pick-up circuit and is provided so thatthe cord circuit under test will always receive two complete applications of testing current. It relays 26 and 25 were not provided,the supervisory relay in the cord under test might receive only a part of the first impulse oftesting current because the interrupter 24 at that instant might have its contacts closed. This interval might be so small that the impulse would not cause the operation of the relay in the cord circuit. The operation of the pick-up feature is as follows. 7

As already pointed out, relay 23 is operated intermittently by the interrupter 2d as soon as the plug of cord A is inserted in jack 12. If the cord is inserted during the time that the contacts of interrupter 24: are closed, relay 26 will not operate because its control throughthe left windingof relay 26. The

cuit is openat the contact of relay 23; As

.- front contact of relay 2O, closed contact and right Winding, of relay 26, winding of relay 25, to battery,-,thereby causing relay 25 to operate. Relays 26 and are maintained energized by the closure of this circuit from the grounded contact of relay 20. lVhen relay 25=operates, itsleft contacteopens the circuit right make contact of relay 25 closes the'following circult: from battery, through supervisory relay-7 of the, cord under test, ring side oflgja-cki'l2, lower backcontact of relay 27,, milliammeter- 13, resistance 1+1, right make-contacts of relays 25 and 23. conductor 43, upperback contact of relay 2?, tip contacts of-jack 12 and plug to ground. As

relay 23 is operating intermittently at the rate of approximately sixty interruptions per minute, the makingand breaking of the circuitgby this relay; as just outlinedcauses the supervisoryrelay in the cord circuit under testto operate intermittently and flash the supervisory lamp associated therenitlu The outer;left make contact of relay 25 closes a circuit tOEtllGCOUHUHQ relays 28, 29, and

'31. These relays Will not start. to function until relay 25 is; energiZed.-. Thus when relay 25 operates, a circuit1s closed upon the operation ofrelay 23 through itsgrounded contact, conductor 33,,outer left-make con tactof relay 25, back contact of relay 29, winding of relay 28 to battery, thus operating the latter relay.

is connected'to bothterminals ofiits Winding.

: As soon as relay 23 is released bythe interrupter 2 1, this ground is removed from the WIIlClIIIg'Ofi relay;2 9=and a-cireuitis closed from battery, Winding of relay 28, Winding.

ofrelay-29, make'contact of relay 28, conductor 48, right contact of relay 22. make contact of relay 20, through grounded con tact 52 of key 21. The closing of this circuit'causesrelay 29 to operate and lock up in series with relay 28. As soon as relay 231s again operated by the interrupter 2 1, ground isv connected over the circuit previously descrlbed, including the outer left contact of relay 25, front contact of relay 29. back contact :of relay. 31, Winding of relay 39. tobattery, thereby causing relay 30 to operate; When relay 23 is again released by in- 2 'round'is disconnected from the terrupter a, g

I circuit just traced, and battery flows through the-windings of relays 30 ancl'31, to front contact of relay 30 over conductor 18 to right make contact of relay 31, conductor Relay" 29, however.v does not. operate at this tune because ground.

grounded contact 52 of key 21. The closing of this circuit causes relays 30 and 31 to lock up. lVhen relay 31 operates, a circuit is closed from grounded contact of key 21, right make contact of relay 20, conductor is, right Winding of relay 22 to battery, thereby causing rel y 22 to operate, The operation of relay 22 closes a locking circuit through its left winding and left make contact from battery, right make contact of relay 20, conductor ll to grounded contact 52. of key 21. The operation of relay 22 at its inner right contact opens the energizing circuit of relay 23 and closes a circuit. through the Winding of rela 3-1 from battery, interrupter 35, conductor 1-7, inner right contact of relay 22, right contact of relay 20,.grounded contact 52'of key 21. The interrupter 35 is of high speed and when the last mentioned circuit is closed relay 31 is operated intermittently about 180 times a minute. Relay 22 is of a quick acting type and operates before relay 53, to be presently referred to, has time to become energized. The operation of relay 22 opens its outer right contact and'breaks the circuit over conductor -18 which maintained counting relays 28, 29, 30 and 31 operated, thereby causing these relays to release.

It should be noted at this point that two complete applications of saturate and release current have been given the supervisory relay in the cord circuit under test. The circuit is now changed so that the operate current is connected in place of the saturate current and the speed of the interrupter is changed from to 180 interruptions per minute.

its soon as relay 22 is operated, the circuit of relay 23 is opened and the circuit of relay 34 is closedinits pl ce; Relay 3-1 over-its right make contact closes the testing circuit over its tip and ring conductors through adjustable resistancelG, thereby giving the supervisory relay its proper operating current. hen relay 34 is first operated'by the interrupter 35'it closes a circuitthrough its left make contact from ground, conductor 33, enter left contact of relay 25 to the counting relays 28, 29, 30, 31, 32 and 33. thereby causing these relays to operate in sequence as previously described in connection with their control by relay The operation-of relay 22 closes a circuit from battery, winding of relay 53, conductor right outer front contact of relay 22, right front contactof relay 20, to grounded contact 52 of key 21. The closure of this circuit causes the operation of relay 53. which supplies ground through its make contact to permit the functioning ofcounting relays 28. 29, 30. 31, 32 and 33 instead of the ground supplied from key 21. as previously described. As soon as relay 3t has been operated and lill released three: times by the interrupter,

thereby connecting three complete applicasory relay in the cord circuit A is open, this tionsof operate and release current to the supervisory relay in the cord circuit under test, all the counting relays mcludlng relay condition is indicated by a tone heard, in thetest receiver 50 which is connected to aplug' inserted in jack 1.1. 'The noise test is arranged so that. it can be made automatically atthe completion of the test ofthe supervisory relays, or it can be made independently of the supervisory relay tests.

For controlling the noise test, key 21 has beenprovided. This key is common to the testing equipment and is mounted with it.

end of the supervisory relay test.

a ing of relay 36.

When key 21 is in its normal position the noise testwill not function; If, however,

key 2l is actuated to connect the winding of relay 36 in series with the winding ofrelay 27 over conductor49,the noise test will be made automatically at the completion of the test of the supervisory relays. hen kev 21 is actuated to connect ground directly to thewinding of'r-elay 27, the noisetest can be first made without testing. the operation of the supervisory relays. The noise testis made by connecting asuitable source of tone 3 through the transformer 37, through a con denser 38 to the midpoint of balanced resistances 39 and 40, the outer terminals of these resistances being connected across the talking conductors of the cord circuit under test.

. The resistances 39 and simulate the resistances in the repeating coil of the cordcircuit A. Since the cord circuit under test is equipped with a supervisory relay, a relay simulating the resistance and operative characteristics of said supervisoryrelay' is provided in the testing circuit in series with resistance 40 to balance the supervisory relay in the cord circuit. The test receiver 50 associated with jack 11 is bridged across the circuit in series with the condenser 41. If the cord under test is in proper condition, no tone will be heard in the receiver 50. If, however, the cord is defective, the tone will be heard, as will presently appear.

Assuming thatthe noise test is to be made automatically at the end of the supervisory relaytest, the operation of thecircuit is as follows: Key 21 is actuated to connect the winding of relay 27 in series with the'winch As already pointed out,relay 33 is the last of the counting relays to operate, this operation taking place at the WVhen relay 33 operates it connects ground from its front contact to the winding of relay 36,.

conductor 49, contact 5lof key .21, winding of relay 27, to battery, thereby operating relays 36 and 27. The operation of relay 36 through its break contact opens the testing circuit over conductor 43 and causesthe lamp associated with the supervisory relay in the cord circuit under test to burn steadily, thereby indicating tothe tester that the circuit is ready for the noisetest. The operation of relay 27 connects the tone and test receiver circuits to the cord under test. "As

soon as the plug of the cord circuit under test is removed from the jack 12, all the relays are restored to their normal positions and the circuit is read for testin another cord.

If the noise-test is to be made without making the supervisory relay test, key 21 is actuated to connect ground directly to the winding of relay 27, thereby causing this relay to operate and connect the tone circuit across the talking conductors of jack '12. The opening of contact 52 'of key 21 removes ground from the contacts of relay20 so that when a cord is inserted in jack 12, and relay 20 operates, its operation does not cause'the testing circuit to function. I

When it is desired to test the operation of the ringing key inthe cordcircuit' under test, key 21 is left in its normal positionso that the noise test willnot functionhiAs soon as the supervisory relay test has been completed, which is indicated by' the supervisory lamp burningsteadily, the ringing key is operated and this connects ringing current across the terminals of relay '42, causing this relay-to operate andremove the ground from the left'low resistance winding of relay 20. When thisground'is removed the lamp in the cord undertest will not receive sutficientcurrent to operate it through the right high resistance winding of relay 20. The lamp will therefore be extinguished, thereby indicating to the tester that the ringing key is in proper operative condition.

What is claimed is:

1. A testing system comprising a cord circuit including supervisory relays, a testing circuit with which the cord circuit may be associated, resistanceelements of different values included in the testing circuit, means for connecting said resistance elements with the supervisory relays, interrupter-s for in termittently operating said means, means including-a plurality of'relays operable sequen tially for automatically releasing one interrupter and substituting another interrupter be associated, resistance elements of: dilfer ent values: lncluded. 1m the .testmgclrcuit,

- means for-connecting said' resistance, ele

ments with the supervisory' relays,- interrupters for intermittently operating; said means, meansrincluding a plurality of relays operable-sequentially, for automaticall releasing one interrupter: after a pre etermined interval: and substituting another interrupter to vary'the speed'ofoperation and resistance conditions towhich said supervisory-relays'are subjected, means for automatically releasing the last mentioned interrupter after a second predetermined interval, and signaling means associated with:

means. for: connecting other' resistance elements With said, relays, an interrupter for intermittentlyoperating-said first means at a: comparatively, slow speed, a second: interrupter-foroperatin said second means at a comparatively rapidaspeed, means includinga: plurality of relaysopemblesequentially forautomaticallyreleasing the first interrupter and. substituting-the second interrupter to varythe speed of operation and :resistance: conditions to which said supervisory' relays are" subjected; and signalingmeans associated with, said supervisory re-' laysfor indicating the action thereof.v

421A testing system comprising a COld2Cl1- cuitt including: supervisory" relays, a testing,

' circuit with which the cord" circuit maybe associated, resistance elements associated with the testing circuit simulating the saturate, release and operating conditions; to: which said supervisory relays are subjected in service, means for:- connecting said re-- sistanceelements-with the supervisory. relays, interrupters of different. speeds foroperatingsaid means, means including a plurality of-rela-ys operable sequentially for automatically releasing'one interrupter fronr control aftersubjecting said relays: to certain tests-at one operatin speed, means for subjecting said relays un er control by another. interrupter'to other tests at a: greater operating; speed, means for automatically releasing the last mentioned interrupter from control of saidrelays" after predetermined; tests thereof, and signaling means associated" with saith-supervisoryrelays for indicating: the action thereof.

5. A testing syste-mcomprising-a rcord circuit including-supervisory relays, atesting' circuit with which the-cord circuit maybe associated, resistance elementsassociated;

with the: testing circuit simulating the 1 saturate, release; andyoperatingi conditions to which;saidrsupenvisonurelays are sub]eotcd in. service, means for" connecting: said resistance; elementsuvitlr the supervisory re lays, interrupter-s of different: speeds, for controllingrsaid: means, means including a plurality of relays operable 1 sequentially for automatically releasing one interrupter from control, aftersnbjectingsaid 1 relays to i a sat-- urate and, releasatest at a relatively low speed, means for-subjecting: said relays to an operati'ngtest under: control by another interrupter" at' a greater speed, means for automatically releasing the last; interrupter fromi control. of said: relays? after a predeterminedinterval of the operating-test, and signaling: means associated; with said supervisory relays for: indicating the action thereof:

6. A. testing system comprising a cordzcircuit including; supervisoryrelays, a testing circuitwith which therord circuit may be associated, resistance: elements of,v difierent values associated with; the: testing circuit simulating the operating conditionsto which' said supervisory relays arei' subjected in service, means for connecting said resistance elements With;the supervisory relays, inter rupters for operating; said means, .means for automatically releasing, one; interrupter and substituting another interrupter-to vary the speed-of operation and: resistance conditions to which said supervisory relays are subjected, artest'. receiver: adapted to be'directly associatedrwith' the ,testingcircuit, and'means for automatically releasing said secondmentioned interrupter: and: associating said" receiver with? the: cord circuit to :determine the operating" condition, of theconductors, of

7 said card .a circuit.

7; A-testingzsystem comprisingacord circuit including supervisory relays, a' testing ClICllltx'WItlIt whichathe' cord may be: associated; resistance, elements associated; with .the

testing; circuit simulating saturate, release and; operating) conditions to which said supervisory, relays are subjected in service'interrupters' of different speed's,,mcans controlled; bysaid interrupters for connecting said'resistance elementsewitli the. supervisory relays, means=fori'automatically transferring the control' from one interrupter; to another interrupter,. means for disconnecting the latter; interrupter; from the testing circuitafter a predetermined interval,-v signaling means associated with. said so er isory. relays 'for indicating the actiont ereof, atest receiver adapted: to be: directlyassociated with the; testing: circuit, and means responsive-"to the disconnection of the second interrupter for associatingthetest receiver with :the cord circuit-to determine the-continuity. of the 'conductors thereof:

'8 testing; system :comprising aacordl circuit including supervisory relays and a ringing key, a testing circuit with which the cord may be associated, resistance'elements associated with the testing circuit simulating operating conditions to which said supervisory relays are subjected in service, interrupters of different speeds, means controlled by said interrupter's for connecting said resistance elements with the supervisory relays, means includin a plurality of relays operable sequentially for automatically transferring the control from one inter rupter to another interrupter, means for disconnecting the latter interrupter after a predetermined interval, means associated with the testing circuit responsive to the operation of said ringing key for applying current to determine its operative condition, and signaling means associated with the cord circuit for indicating the action of said relays and said ringing key.

9. A testing system comprising a cord circuit including supervisory relays, a testing circuit with which the cord circuit may be associated, a test receiver adapted to be associated with the testing circuit and thereover with the cord circuit to determine the continuity of the conductors of the cord circuit, resistance elements of different values included in the testing circuit, means for connecting said resistance elements with the supervisory relays, interrupters for intermittently operating said means, means including a plurality of relays operable sequentially for automatically releasing one interrupter and substituting another interrupter to vary the speed of operation and resistance conditions to which said supervisory relays are subjected, signaling means associated with said supervisory relays for indicating the action thereof, and means for automatically disconnecting the last inter rupter from the testing circuit after apre determined interval and associating said test receiver withsaid cord circuit.

10. A testing system comprising a cord circuit including supervisory relays, a testing circuit with which the cord circuit may be associated, resistance elements of diflerent values included in the testing circuit, means for connecting said resistance elements with the supervisory relays, interrupters for intermittently operating said means, means including a plurality of relays operable sequentially for automatically releasing one interrupter after a predetermined interval and substituting another interrupter to relays are subjected, means for automatically releasing the last mentioned interrupter after a second predetermined interval,

signaling means associated with said supervisory relays for indicating the action thereof, a test receiver adapted to be associated with the testing circuit and thereover with the cord circuit to determine the continuity of the conductors of said cord circuit, means for associating said test receiver with the cord circuit to make tests of its conductors independently of supervisory relay tests, and means for associating said test receiver with the cord circuit upon the release of said second interrupter.

11. A testing circuit comprising a cord circuit including supervisory relays and a ringing key, a testing circuit with which the cord circuit may be associated, resistance elements of different values included in the testing circuit, means for connecting certain of said resistance elements with the supervisory relays, a second means for connecting other resistance elements with said supervisory relays, an interrupter for intermittently operating said first means at a comparatively slow speed, a second interrupter for operating said second means at a com paratively rapid speed, means including a plurality of relays operable sequentially for automatically releasing the first interrupter and substituting the second interrupter to vary the speed of operation and resistance conditions to which said supervisory relays are subjected in service, means associated with the testing circuit responsive to the operation of said ringing key for applying current to determine its operative condition, signaling means associated with said supervisory relays for indicating the action of said relays and said ringing key, a test receiver adapted to be associated with said testing circuit and thereover with said cord I circuit to determine the continuity of the conductors of the cord circuit, and means for connecting said test receiver to make independent tests and also to make such tests in conjunction with other of the above tests automatically upon the release of said second interrupter.

In testimony whereof I have signed my name to this specification this 2nd day of July, 1925.

JOHN F. TOOMEY. 

